Klinefelter syndrome (KS) is characterized by an additional X chromosome in males leading to a karyotype of 47,XXY. It is associated with an increased risk of certain malignancies, including leukemia, breast cancer and extragonadal germ cell tumor such as mediastinal germ cell tumors and rarely intracranial germ cell tumors. It is possible that the increased risk of developing certain cancers can be attributed to a direct effect of the chromosomal abnormality or the combined action of the abnormal chromosomes and hormonal imbalances. Here we describe a synchronous occurrence of bifocal intracranial germinoma and bilateral testicular epidermoid cyst in an adolescent patient with Klinefelter`s syndrome. The synchronous occurrence of the dual tumors in this patient with Klinefelter`s syndrome might be resulted from the migration defect during embriyogenesis due to underlying genetic disease or it is a coincidental condition, yet there has been no case reported in the literature, so far.

Keywords: Klinefelter`s syndrome, bilateral testicular epidermoid cyst, germinoma